JPH08336825A - Method for feeding reinforcing fibers - Google Patents

Abstract

PURPOSE: To provide a method for opening reinforcing fibers and feeding them into a matrix without spoiling fiber properties and to use it in the manufacturing process for secondary fiber products of a concrete mortar as an apparatus to be used can be miniaturized. CONSTITUTION: In a method for dispersing and feeding reinforcing fibers with a denier of 100-5,000dr and an aspect ratio of 30-200, the fibers are dispersed and fed by vibrating a basket 1 consisting of mesh-like substance with a mesh having a mesh size one to three times the fiber length.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of introducing reinforcing fibers into a matrix. In particular, it is preferably used as a method of adding fibers to a hydraulic matrix such as concrete.

[0002]

2. Description of the Related Art Hydraulically molded products represented by concrete have high compressive strength, are non-combustible materials, have durability, and are inexpensive, so they are consumed in large quantities as civil engineering and construction materials. Since it has the drawback of being extremely weak against bending stress and bending stress, it is widely practiced to mix and reinforce steel fibers. However, the steel fiber not only has the problems of rusting and corrosion, but also because the fiber is heavy and difficult to carry, a large facility is required especially for charging the kneading machine. Therefore, synthetic fibers such as polyvinyl alcohol (PVA) fibers are used as reinforcing fibers.

When a synthetic fiber is used as the reinforcing fiber, there is no problem in terms of performance, but with respect to the addition to the kneading machine,
There were various problems not found in steel fibers. That is, when the fibers are put into a kneading machine in a state where they are not sufficiently dispersed, the fibers are entangled with each other to form a lump (fiber-ball).
Was likely to occur, and the apparent specific gravity was small, making it difficult to handle in a narrow space. In particular, recently, PVA short fibers having an extremely large fineness and high strength and Young's modulus have been found to be excellent in the reinforcing effect, and have been attracting attention.
On the other hand, the fibers tend to be entangled (in a concrete state, many rod-shaped objects are easily aggregated in a state where they are oriented in a free direction) to form a three-dimensional lump, which is even in the kneading machine. And, it is difficult to throw it in a sufficiently dispersed state. As a method of solving such a problem, a method of forming a pair of movable bodies having a large number of needle-like protrusions on the surface into a single fiber by the relative movement of the needles (JP-A-58-18).
1760) and a method of scraping fibers by rotating a rotor having a large number of needle-like projections on the tip of a belt conveyor (Japanese Patent Laid-Open No. 1-105704).

[0004]

When the needle-like projections are used to separate the fibers, the fibers are damaged and the original strength of the fibers cannot be fully utilized, so that the reinforcing effect is insufficient. Further, in the above method of scraping off with a rotor, there is a problem that the fiber supply device becomes very large and it is difficult to use in a narrow construction site. In view of the above problems, the present invention provides a method for easily adding reinforcing synthetic fibers to a matrix without causing dispersion failure.

[0005]

The present invention has a fineness of 100 to 100.
In a method of dispersing and reinforcing synthetic fibers for reinforcement having a dr of 5000 dr and an aspect ratio of 30 to 200 into a matrix, the fibers are dispersed and charged by vibrating a cage made of a mesh-like material having meshes of 1 to 3 times the fiber length. The present invention relates to a method for adding reinforcing fibers. According to the present invention, since the fibers are not forcibly separated by the needle-like protrusions and the fibers are separated only by passing through the mesh-like metal net, the fiber performance is not impaired and a sufficient reinforcing effect can be obtained. According to the conventional method, damage to fibers of 500 dr or less was particularly large, but according to the present invention, excellent effects can be obtained even with fibers of 500 dr or less.

The kneading machine for kneading the reinforcing fibers and the matrix has already been put into practical use for steel fiber kneading, and for example, various types of kneading such as a biaxial forced agitation type and a tilting type are available. Although there is a mixer, the present invention can be used with any type of mixer. The reinforcing fiber used in the present invention has a fineness of 100 to 50.
00 dr and an aspect ratio of 30 to 200. If the fineness is less than 100 dr, the separating property and kneading and mixing become insufficient, and conversely, if it exceeds 5000 dr, the reinforcing effect becomes insufficient. If the aspect ratio is less than 30, the fibers may be pulled out, resulting in poor reinforcement and conversely 2
If it exceeds 00, the separation will be poor. In terms of dispersibility and reinforcement, fineness of 200 to 500 dr, aspect ratio of 5
Those of 0 to 150 are preferable. In the present invention, the aspect ratio is the fiber length A of the pulp-like material divided by the diameter B of the circle having the same area as the cross-sectional area of the pulp-like material. Further, from the viewpoint of reinforcing property, a material having a strength of 5 g / d or more and a Young's modulus of 100 g / d or more, particularly a strength of 8 g / d or more and a Young's modulus of 250 g / d or more is more preferable. The method of the present invention is particularly suitable for PVA-based fibers, but can naturally be applied to organic fibers such as aramid, polypropylene, acrylic and polyarylate having the above-mentioned fineness and aspect ratio.

The present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an example of an apparatus used in the present invention, and FIG. 2 is an elevation view thereof. In these figures, 1 is a mesh basket, 2
Is a vibration motor, 3 is a mesh basket vibration flank, 4
Is a fiber guide cover, 5 is a column, 6 is a vibration crank bar, and 7 is a mesh cage vibration fulcrum bar. Generally, the fibers are contained in a bag or a cardboard case, which is placed in a mesh basket. This mesh basket is a hopper
It also plays a role of fiber separation. The function as a hopper is fulfilled by the vibrating fulcrum bar portion of the mesh basket. Its function can be changed by changing the volume and shape of the basket.

The discharge amount of the separated fibers can be adjusted by the size of the mesh of the mesh basket, the amplitude of the mesh wire mesh, and the frequency. It is preferable that the frequency is 50 to 200 times / minute and the stroke is 50 to 100 cm. It is preferable that the bottom surface and the side surface of the basket have a mesh shape, but only a part of the side surface or the bottom surface may be made of a mesh material. The mesh size of the mesh-like material is related to the aspect ratio of the fiber, but is preferably 1 to 3 times, especially 1.5 to 2.5 times the fiber length. The material of the basket is not particularly limited, and examples thereof include those made of wire mesh, plastic, and the like. The shape of the basket may be set appropriately.

It is preferable that a part of the basket (a part to which the vibration crank bar is attached) is squeezed to be thin (see FIG. 2). In other words, if you put a lot of fibers in the basket,
Even if the basket vibrates, the fibers do not move much due to the weight of the piled fibers, making it difficult to separate the fibers. However, when a part of the basket is squeezed to be thin, the weight of the fiber charged in the upper part of the basket is partly reduced, so that the fiber is likely to move due to vibration, and the fiber can be separated. The aperture gradient a as shown in FIG. 2 is preferably 50 to 80 degrees, preferably 65 to 75 degrees. The throttle gradient a in the present invention means the angle of the recessed portion formed on the side surface of the basket with respect to the horizontal plane. Further, in order to make the discharge amount of the divided fibers constant over time, it is preferable to use a conveyor and supply so that the thickness of the fiber group on the conveyor becomes substantially uniform.

As an apparatus for separating a fiber group into almost single fibers, in addition to the apparatus used in the present invention, for example, a blade that rotates at high speed in a drum by utilizing centrifugal force is a fiber. A structure that breaks the lumps and splashes it to the drum wall, a structure that uses a mesh to rotate the blades in the drum of a coarse mesh to separate the fibers and drop the fibers from the gaps of the mesh, There is a structure in which a bar is vibrated in a chamber having a horizontal bar having a gap at the bottom to scrape fibers from the gap between the horizontal bars. All of these are intended for steel fibers, and even when synthetic fibers having remarkably different specific gravities and physical properties are used in these steel fiber devices, the fibers are bent and damaged, resulting in fiber splitting and Uniform dispersibility (time and area)
In this respect, a preferable result cannot be obtained. The present invention, as described above, solves the problems of splitting property and uniform dispersibility without substantially damaging the fibers.

Further, conventionally, for the purpose of opening a fiber lump such as wool, a method of opening the fiber lump sent by a conveyor belt by using a device called a fairnote is generally adopted. However, this device has a large cylinder having a large number of protrusions on the surface thereof and a large number of cylinders having a large number of protrusions around the large cylinder.
While moving between the large cylinder and the small cylinder by the rotation of, the fiber clumps are separated into small clumps or single fibers while reaching from the one side to the other side of the large cylinder. As is clear from this, the device used in the present invention is completely different from the device called a fairnote. When the above-mentioned fairnote is used in the method of the present invention, the fibers are not only preferable because they are torn in the longitudinal direction and suffer many scratches.

The object to be reinforced (matrix) used in the present invention is not particularly limited, but a typical example is cement. Specifically, Portland cement and various other cements are used, but gypsum, gypsum slag, magnesia, etc. can be used, and these may be used alone or in combination. Mixing siliceous materials such as silica sand and diatomaceous earth with calcareous materials such as cement, slaked lime and quicklime, mica,
Auxiliary materials such as sepiolite, attabalgite, and perlite can be used. Further, these hydraulic materials may be mixed with sand or gravel to be used as mortar or concrete.

The present invention will be described in detail below with reference to examples, but the examples are not intended to limit the invention in any way.

EXAMPLE A secondary product containing reinforcing fibers was manufactured with the following specifications using the apparatus shown in FIGS. 1 to 3 for the purpose of reducing the weight of the soundproof wall. Fiber specifications Material PVA Fineness 350 dr Cut length 24 mm Aspect ratio 120 Strength 9 g / d Young's modulus 300 g / d Fiber feed amount 1 kg / min Mixing ratio 1 vol% / Mortar hopper-Fiber amount 5 kg

The device is a pan mixer (capacity 0.5
The mechanical conditions of the basket type loading device installed on the machine stand of m ³ ) are as follows: mesh size of the entire surface 60 mm (about 2.5 times the fiber length) Frequency 130 times / min Stroke 70 cm Hopper-Max Diameter 800φ Hopper squeezing gradient a 70 ° Under the above conditions, fibers were dispersed into a 380 l kneading mortar in a pan mixer at a rate of 1 kg / min. As a result, the introduced fibers were uniformly dispersed and mixed in the mortar without substantially producing fiber balls. In the past, since fiber balls were generated, it was necessary to separate the fibers by human power for about 10 minutes, but according to the present invention, it is possible to reduce labor and kneading time due to human power, The process was stabilized and the quality of the product was improved.

[0015]

EFFECTS OF THE INVENTION The present invention provides a method for separating reinforcing fibers into a matrix without impairing the fiber performance, and since the apparatus used can be downsized,
The concrete mortar can now be put to practical use in the secondary fiber product manufacturing process.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of an apparatus capable of implementing the present invention.

2 is a side view of the device shown in FIG. 1. FIG.

FIG. 3 is a side view of the device shown in FIG.

[Explanation of symbols]

 1: Mesh cage 2: Vibration motor 3: Mesh cage vibration crank 4: Fiber induction cover 5: Struts 6: Vibration crank bar 7: Mesh cage vibration fulcrum bar 8: Squeeze angle of cage (A)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kamiji Saito 1-2-1, Kaigandori, Okayama-shi Kuraray Co., Ltd.

Claims (1)

[Claims] 1. A basket comprising a mesh-like material having a mesh size of 1 to 3 times the fiber length in a method of dispersing and reinforcing synthetic fibers for reinforcement having a fineness of 100 to 5000 dr and an aspect ratio of 30 to 200 into a matrix. A method for introducing reinforcing fibers, characterized in that fibers are dispersed and introduced by vibrating.